My gears are driving me nuts. I can’t manage to index my XT front derailleur to down shift to the middle ring. It drops nicely into the smallest and up shifts to top and middle perfectly. Downshifting to middle just leaves the chain on the top ring making a racket.

I have replaced the gear cable and spent ages fiddling. I had it working in the stand (just) but as soon as I start riding it goes again. Now I have no luck on the stand or on the trail.

It makes no difference what rear gear I am in.

What to try next?

Does the top adjustor leave the mech to far to the right? Cable too tight?

If the mech is a few years old it may have developed some play in the pivots. In this case the pressure of the chain against the mech is enough to overcome the mech’s inbound movement a bit and prevent it dropping.